Electron Microscopic Studies of Palmer and Plantar Pits of Nevoid Basal Cell Epithelioma

Abstract

Light and electron microscopic observations were made on seventeen palmar or plantar pits of the nevoid basal cell epithelioma syndrome. In two specimens, typical basal cell epitheliomas were seen arising from the epithelium at the base of the pits; one of them was a pigmented basal cell epithelioma. The epithelium under the pit was stained only weakly with azure B; this was attributed to a very poor development of tonofibrils. Keratohyaline granules were small and the discharge of the cementsomes was incomplete. Premature desquamation of the horny cells took place along the intercellular spaces and was not due to degeneration of horny cells. It was thought that incomplete discharge of cementsomes, perhaps due to shortened transit time of keratinocytes, failed to provide enough intercellular cement. Surrounding the rete ridges and particularly surrounding the fully grown tumor, collagen stroma showed various degrees of dissolution.